A meeting, in particular a meeting of people whose goal is political or organizational change. In American presidential politics, the word has come to mean a gathering of each party’s local political activists during the presidential nomination process. In a “layered” caucus system, local party activists, working at the precinct level, select delegates to county meetings, who in turn select delegates to state meetings. These state-level conventions select delegates to their party’s national nominating convention. The purpose of the caucus system is to indicate, through delegate choice, which presidential candidate is preferred by each state party’s members. Its effect is to democratize presidential nominations, since candidate preferences are essentially determined at the precinct level, at the beginning of the process.

This definition is in context to Political. See more contextual defintions for Caucus.